As long as a person is alive, he should prepare himself for the World to Come with Torah and mitzvas. One can compare this to a rich person who was falsely charged with trading in contraband and sentenced to death, and his relatives and friends managed to mitigate his punishment to exile with minimal food rations. Although he will be very happy that he was saved from death, he will still fear the starvation ahead of him. So too, after a person suffers in gehinom, if he did not prepare sufficient Torah and mitzvas to sustain himself in the World to Come, he may exist in that world, but will suffer eternal starvation. Therefore, as long as person is alive, he should fill his bags for the long journey ahead of him, so he can properly enjoy his eternal existence.
כ״ד בתמוז ה׳תש״פ
"והאמת בלתי שום ספק כלל, שאם היה העולם כולו מקצה עד קצהו פנוי חס ושלום אף רגע אחד ממש מהעסק והתבוננות שלנו בתורה, כרגע היו נחרבים כל העולמות, עליונים ותחתונים, והיו לאפס ותוהו חס ושלום". (נפש החיים) 1